1. Field of the Invention
The present invention pertains to a pallet dispenser that can receive a vertical stack of skewed or misaligned pallets in an interior of the pallet dispenser and align the pallets as they are sequentially dispensed from the pallet dispenser onto a conveyor below the pallet dispenser. More specifically, the present invention pertains to a pallet dispenser that can be quickly manually changed over to accommodate pallets of different sizes and vertically dispense the pallets one by one onto a conveyor below the pallet dispenser.
2. Description of the Related Art
There are many different known types and sizes of pallet constructions that are employed in supporting goods when being shipped. The pallets are designed to be lifted by conventional forklift trucks and provide a base for large goods or for large numbers of goods that would be difficult to be manually lifted and transported. By supporting large, heavy goods or large numbers of goods on a pallet, the goods can be easily transported, for example from a loading dock to a truck bed or vice versa, by a conventional forklift truck.
Most conventional pallets are constructed of wood and/or plastic and are intended to be reused several times. Emptied pallets that are to be reused are usually stacked upon each other in a storage area until they are needed. Often the stacking of the used pallets is done manually as the pallets are emptied, resulting in skewing or misalignment of the vertically stacked pallets in many instances. What is meant by skewing or misalignment is that the sides of the pallets in the vertical stack are not aligned and adjacent pallets are staggered or slightly turned relative to each other.
In pallet dispensers that are employed in combination with conveyor systems, the skewing or misalignment of pallets loaded into the pallet dispenser must be corrected before the dispenser dispenses a pallet onto the conveyor system. This is necessary so that the pallets dispensed onto the conveyor system are properly oriented relative to the conveyors so that goods to be loaded onto the pallets conveyed by the conveyor system are properly positioned on the pallets. For example, in an automated conveyor system that stacks layers of rows of goods on a pallet conveyed through the system, the pallet must first be correctly oriented relative to the conveyor in order to ensure that the layers of rows of goods are properly positioned on the pallet.
To achieve the proper orienting of the pallets dispensed from a pallet dispenser onto a conveyor system, prior art pallet dispensers typically had guide rails at their opposite sides and their fronts and backs that would engage the four sides of a pallet as it is dispensed from a vertical stack of pallets positioned in the interior of the pallet dispenser. The guide rails would engage with the four sides of the pallets as they are dispensed vertically downward through the pallet dispenser and orient the bottom most pallet of the stack just prior to its being dispensed onto the conveyor system below the dispenser.
However, pallets are manufactured in a variety of sizes and primarily in a large size that measures 56xe2x80x3 by 44xe2x80x3 and a small size that measures 48xe2x80x3 by 40xe2x80x3. If a stack of small pallets is loaded into a pallet dispenser whose guide rails have been previously adjusted and set to reorient a stack of large pallets, the guide rails of the pallet dispenser would have to be manually adjusted to reorient the small pallets of the stack of pallets loaded into the pallet dispenser. Additionally, if a stack of large pallets is to be loaded into a pallet dispenser that had been previously adjusted to dispense a stack of small pallets, the guide rails of the pallet dispenser would have to be manually adjusted and reset in order to first receive the stack of large pallets in the interior of the pallet dispenser and then to properly orient the large pallets as they are dispensed from the pallet dispenser. Because prior art pallet dispensers typically would have guide rails on all four sides of the dispenser to engage all four sides of the pallets dispensed vertically downward through the dispenser, adjusting the positions of guide rails to accommodate stacks of different size pallets would require a considerable amount of labor time. This labor time was not only down time for the pallet dispenser as its guide rails are adjusted, but also down time for the entire conveyor system as the system waits for additional pallets to be dispensed by the pallet dispenser. This down time significantly decreases the cost efficiency of running a conveyor system.
Furthermore, large pallets and small pallets differ in their construction in that the cross beams of the pallets that are spatially arranged between the top and bottom panels of the pallets or the top and bottom sheets or boards of the pallets usually have a different spacing between the beams. The prior art pallet dispensers would have actuator arms that would project horizontally into the interior volume of the pallet extending between the cross beams of the bottom most pallet of the stack and thereby support the vertical stack of pallets in the pallet dispenser interior. Retracting the actuator arms would cause the bottom most pallet to be dispensed downwardly onto the conveyor, a portion of which would typically be raised to receive the bottom most pallet. As the portion of the conveyor is lowered after receiving the bottom most pallet, the actuator arms would again be extended into the pallet dispenser interior to engage between the crossbeams of the next pallet of the stack and support the stack of pallets in the pallet dispenser interior as the previously dispensed pallet is lowered and conveyed out of the dispenser. Because large and small pallets have different numbers of cross beams that have different positions in the pallets, it would also be necessary to adjust the length of the actuator arms when the pallet dispenser is to be changed over from dispensing large pallets to dispensing small pallets, or vice versa.
What is needed to overcome the disadvantages associated with prior art pallet dispensers is a way of quickly changing over the pallet dispenser to accommodate vertical stacks of pallets of different sizes.
Much of the construction of the pallet dispenser of the invention is similar to that of prior art pallet dispensers and therefor is not described in detail. The pallet dispenser is basically comprised of a rectangular base that is dimensioned to support both large and small pallets in an interior area of the base above a conveyor apparatus with which the dispenser is used. The conveyer is not part of the invention but a typical conveyor employed with pallet dispensers has a portion positioned beneath the pallet dispenser that raises to accept a pallet at a bottom of a vertical stack of pallets supported by the dispenser and then lowers incrementally to enable the pallet dispenser to engage with the next pallet above the pallet on the conveyor so that the pallet on the conveyor can be separated from the remainder of the pallets in the vertical stack supported in the interior of the pallet dispenser.
The bottom most pallet is separated from the remainder of the pallets in the vertical stack by actuator arms of the dispenser supported on the base. The actuators of the actuator arms cause the arms to swing out from the base through an arc to positions where they project inwardly from opposite sides of the base toward the base interior. As the arms are actuated and swing out through the arc of movement, they pass between the top and bottom panels of the pallet to be engaged by the arms and in between cross beams of the pallet. However, because the pallet dispenser of the invention is designed to dispense both large and small pallets, the actuator arms of the dispenser are modified. The modification is necessary because longer actuator arms needed to reach into the pallet dispenser interior a sufficient distance to engage with smaller pallets would likely engage with cross beams of larger pallets loaded into the pallet dispenser interior before they complete their arc of movement. To avoid this problem, the actuator arms of the invention are constructed in two parts that are connected to each other for linear sliding movement between at least two adjusted lengths of the actuator arms. A manually operated pin holds the actuator arms in their two adjusted length positions. In this manner, the lengths of the actuator arms can be increased to engage small pallets stacked in the pallet dispenser and the lengths of the actuator arms can be decreased to engage large pallets stacked in the pallet dispenser.
A frame of the pallet dispenser extends upwardly from a top of the base. The frame has an interior positioned above the base interior and is dimensioned sufficiently large to receive a vertical stack of large pallets in the frame interior. The frame supports vertical upright assemblies at the opposite left and right sides of the pallet dispenser and supports a rear vertical upright assembly at the rear of the pallet dispenser. The front of the frame is basically left open to provide sufficient access for a forklift truck to deposit a stack of pallets into the frame interior through the front of the frame.
Each of the left and right vertical upright assemblies and the rear upright assembly is comprised of a pair of rails that are suspended from pivot connections of the rails at the top of the frame. Each pair of rails hangs downwardly through the frame interior to bottom portions of the rails that are angled inwardly toward the frame interior. The pairs of rails are designed to guide pallets in a vertical stack toward the center of the pallet dispenser base as pallets are-sequentially dispensed vertically downward through the frame interior. The inwardly angled portions of the rails at their bottom ends orient the lower pallets of the stack in their desired position relative to the conveyor with which the dispenser is used just prior to the pallets being dispensed onto the conveyor.
Each of the vertical upright assemblies is provided with a manual handle that is used to move the vertical upright assemblies between first and second adjusted positions of the assemblies relative to the frame. In the first positions of the vertical upright assemblies, their rails are moved inwardly toward the frame interior. In their first positions, the left and right side vertical uprights and the rear vertical uprights guide a stack of small pallets vertically downward through the frame interior. The inwardly angled lower portions of the rails of the upright assemblies orient the bottom most pallet of the stack of small pallets in its desired orientation prior to being deposited onto the conveyor beneath the dispenser. When the manual handles of the vertical upright assemblies are moved toward their second positions, the rails of the vertical upright assemblies are moved outwardly away from the frame interior to their second positions. In the second positions of the rails, the lower portions of the rails orient the bottom most pallet in a stack of large pallets in its desired position prior to being dispensed onto the conveyor below the dispenser.
The manual handles of each of the vertical upright assemblies are basically comprised of pivot shafts at opposite sides of the assemblies that are mounted in bushings on the dispenser base and horizontal rods that are mounted to the shafts at opposite ends of the rods. A manual hand hold is mounted to each rod intermediate its opposite ends. The shafts provide a pivoting connection of the rods and the hand holds to the base that pivots about a horizontal axis of the shafts. By gripping the hand holds, the rods can be pivoted about the shafts and moved through an arc toward the frame interior to first positions of the manual handles and away from the frame interior to second positions of the handles. The opposite ends of the rods engage in vertical slots of the pair of rails of the vertical upright assemblies for sliding movement of the rod ends through the slots as the rods are moved through an arc between their first and second positions. Moving the rods to their first positions causes the vertical upright assemblies to move to their first positions relative to the frame, and moving the rods to their second positions causes the vertical upright assemblies to move to their second positions relative to the frame. In this manner, the manual handles provide a mechanism by which the positioning of the vertical upright assemblies can be easily and quickly adjusted between their first and second positions in a very small amount of time.
A pair of guides are mounted to the base at the front of the frame for linear sliding movement toward and a away from the frame interior. The guides have angled orientations similar to those of the lower inwardly angled positions of the rails of the vertical upright assemblies. The guides at the front of the dispenser assembly are much shorter than the suspended rails of the vertical upright assemblies enabling a forklift truck to lift a stack of pallets over the guides and then deposit the stack of pallets downwardly into the dispenser interior. The guides are each mounted for sliding movement between first and second positions relative to the base of the dispenser. The guides have pins that can be pulled manually out from the guides to disengage the guides from the base enabling them to be moved between their first and second positions and then the pins are dropped into a corresponding hole in the guide slide that holds the guide in its adjusted position. Again, by providing the sliding connections of the guides to the base and the pins that hold the guides in their adjusted positions, the guides can be quickly and easily adjusted between their first and second positions relative to the pallet dispenser base.
The pallet dispenser assembly described above provides quick and easy adjustments of the vertical uprights and guides of the pallet dispenser to enable it to receive large or small pallets and quickly adjust to accommodate the pallets so that the pallets are properly oriented relative to a conveyor with which the dispenser is used prior to the dispenser assembly dispensing the pallet onto the conveyor.